1. Field of the Invention
The invention relates to an erasable printing plate and to a process and an apparatus for erasing and regenerating the printing plate.
2. Discussion of the Prior Art
A printing plate suitable for the wet offset method is disclosed in DE 42 35 242 C1. This printing plate has strong microdipoles at least in its outer layer, and its surface is hydrophobic. After application of covering material corresponding to an image to be printed, the non-image parts are hydrophilized by a hydrophilizing agent. It is true that these printing plates have the advantage that they can readily be regenerated, i.e. after completion of a printing process they can be erased in a simple manner and provided with further images. However, these printing plates have the disadvantage that it is expensive to produce them.
Regeneration processes which are suitable for smooth as well as rough, porous printing plates of ceramic, glass or anodized aluminum are disclosed in DE 41 23 959 C 1. The disadvantage of these regeneration/erasing processes is that they are technically relatively complicated and expensive to carry out.